Communication devices such as wireless devices may be also known as e.g. user equipments (UEs), mobile terminals, wireless terminals and/or mobile stations. A wireless device is enabled to communicate wirelessly in a cellular communications network, wireless communications system, such as a telecommunications system, or radio communications system, sometimes also referred to as a cellular radio system, cellular network or cellular communications system. The communication may be performed e.g. between two wireless devices, between a wireless device and a regular telephone and/or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the cellular communications network. The wireless device may further be referred to as a mobile telephone, cellular telephone, laptop, Personal Digital Assistant (PDA), tablet computer, just to mention some further examples. The wireless device may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data, via the RAN, with another entity, such as another wireless device or a server.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area is served by at least one base station, e.g. a Radio Base Station (RBS), which sometimes may be referred to as e.g. “eNB”, “eNodeB”, “NodeB”, “B node”, or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided according to a Radio Access Technology (RAT) and at a carrier frequency by the base station at a base station site. The base station may support one or several communication technologies, such as RATs. Cells may overlap so that several cells cover the same geographical area. By the base station serving a cell is meant that the radio coverage is provided such that one or more wireless devices located in the geographical area where the radio coverage is provided may be served by the base station. One base station may serve one or several cells. When one base station serves several cells, these may be served according to the same or different RATs, and/or may be served at same or different carrier frequencies. The base stations communicate over the air interface operating on radio frequencies with the wireless device within range of the base stations.
In some RANs, several base stations may be connected, e.g. by landlines or microwave, to a radio network controller, e.g. a Radio Network Controller (RNC) in Universal Mobile Telecommunications System (UMTS), and/or to each other. The radio network controller, also sometimes termed a Base Station Controller (BSC) e.g. in GSM, may supervise and coordinate various activities of the plural base stations connected thereto. GSM is an abbreviation for Global System for Mobile Communications (originally: Groupe Special Mobile). In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or eNBs, may be directly connected to other base stations and may be directly connected to one or more core networks.
UMTS is a third generation mobile communication system, which evolved from the GSM, and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology. UMTS Terrestrial Radio Access Network (UTRAN) is essentially a radio access network using wideband code division multiple access for wireless devices. High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), defined by 3GPP, that extends and improves the performance of existing 3rd generation mobile telecommunication networks utilizing the WCDMA. Moreover, the 3GPP has undertaken to evolve further the UTRAN and GSM based radio access network technologies, for example into evolved UTRAN (E-UTRAN) used in LTE.
The expression downlink (DL) is used for the transmission path from the base station to the wireless device. The expression uplink (UL) is used for the transmission path in the opposite direction i.e. from the wireless device to the base station.
Massive deployment of wireless sensors has, and is increasingly, taken place in particular 3GPP networks. The type of communication generated by such devices is termed Machine To Machine (M2M) communication or Machine Type Communication (MTC). The devices typically do not use a lot of power and since they are required to be of low cost, they typically do not have advanced processing chains either in the transmitter or in the receiver part. Information on M2M & MTC may e.g. be found in:
Institute of Electrical and Electronics Engineers (IEEE) 802.16p-10/0004r3 “IEEE 802.16p Machine to Machine (M2M) System Requirements Document (SRD)” (2011-10-09),
Technical Specification (TS) 22.368 V11.6.0 “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service requirements for Machine-Type Communications (MTC); Stage 1” (Release 11), and
European Telecommunications Standards Institute (ETSI) TS 102 689 V1.1.1 (2010-08) “Machine-to-Machine communications (M2M); M2M service requirements”. These documents i.a. specify communication between Machine Type Devices (MTDs) without human interaction for the sake of control, automation and other functions. Radio traffic generated by MTDs, such as wireless sensors of the above kind, i.e. including M2M communication and MTC, will thus cause load in the wireless communications systems where they are deployed, e.g. LTE based wireless communications systems, and in cells thereof. This load is in addition to load resulting from more conventional radio traffic. More conventional radio traffic refers to radio traffic generated by wireless devices associated with human users. Hence, the additional load from radio traffic, i.e. radio traffic load, generated from MTDs has to be taken care of and dealt with in wireless communications systems.